The present invention relates to performing efficient comparison operations on encrypted data, and more specifically to a comparison operation providing a result of an encryption of “one” when two values to be compared are equal and an encryption of “zero” when two values to be compared are unequal.
Zvika Brakerski, Craig Gentry, and Vinod Vaikuntanathan, 2012, “Fully homomorphic encryption without bootstrapping”, in Proceedings of the 3rd Innovations in Theoretical Computer Science Conference (ITCS '12), ACM, New York, N.Y., USA, 309-325 discloses a fully homomorphic encryption (FHE) scheme based on the ring learning with error (RWLE) scheme that have 2λ security against known attacks. This scheme will be referred to as the “BGV scheme”.